25 Years of kidney transplant survival

Monkey YM received a kidney transplant 25 years ago and is still in good health, despite receiving no immunosuppressive treatment for the last 24 years. The success rate of human kidney transplants has increased dramatically during those 25 years, in part because of lessons learnt from research in animals.

We survive only because our bodies have highly sophisticated immune systems that are able to recognise and attack foreign organisms while leaving the self unharmed. In this way infections with bacteria and viruses are generally controlled by protective immune responses without harming ourselves. This immune attack on non-self has major implications for organ transplants, because organ transplants are also seen as foreign and attacked. The ultimate goal in organ transplantation is to turn off the immune attack on the transplanted organ while leaving other protective immune responses unaffected, a so-called state of tolerance.

Patients on dialysis often have anaemia due to blood loss, which used to be replaced by blood transfusions. About 30 years ago it became possible to use a new drug, EPO, to stimulate blood production and this replaced blood transfusion as the method of choice. Unfortunately, at the same time kidney transplant success rates deteriorated, even though new immunosuppressive drugs such as cyclosporins were also being used that were able to switch the immune system off.

It seemed possible that in some way the blood transfusions had helped survival of the transplanted organ, but how? As a result 25 years ago monkey YM participated in a study to investigate what might be going on and received blood transfusions before a kidney transplant and immunosuppressive drugs afterwards for one year. YM did not reject the kidney after immunosuppression was stopped and is still alive and in good health today because there has been a lack of immune response to the new kidney over this 25 year period.

Research has implicated a molecule called TGF-beta in this success and it seems that another molecule IL-10 may also be involved. Currently research is looking to see how this has been maintained over such a long period of time. A better understanding of this is likely to have important consequences for human organ transplants in the future as longer transplant survival times are sought